In recent years, medical-purpose endoscopes have been widely adopted in order to observe an intracavitary organ by inserting an elongated insertion unit, which has flexibility, into a body cavity, or to perform various cures or treatments with a treatment instrument passed through a channel that lies through the insertion unit. Moreover, industrial-purpose endoscopes have been used to observe internal corrosive states of pipes in buildings.
For insertion of an endoscope in various examinations, a doctor or an engineer who is an operator judges a direction of advancement while viewing an endoscopic image.
On the other hand, an inserting procedure for examining the large intestine is hard to do and requires expertise. This is because the shape of the large intestine is complex, the lumen of the large intestine is narrow, and the shape of the large intestine or the lumen thereof is different from person to person. Moreover, since insertion must be performed reliably and carefully, a doctor who has little experience incurs a large load.
An endoscope is inserted basically in a direction in which a lumen extends. However, the direction of a lumen is not always seen within a field of view offered by an endoscope system. When the endoscope has approached a tortuous region of the large intestine (the sigmoid colon, a curvature of the liver or spleen, or the like) or an intestinal wall or fold thereof, a doctor who is an operator must judge from his/her experience and knowledge in what direction the endoscope should be inserted.
In order to cope with the above situation, a doctor has to experience many examinations so as to be able to determine under various criteria in what direction the endoscope should be inserted.
However, a doctor who is inexperienced has a little knowledge or experience in determining what information should be used to make a judgement in what manner. Consequently, it becomes necessary to withdraw an endoscope for the purpose of catching a lumen in a field of view again. This leads to an increase in examination time or patient discomfort.
Moreover, when an endoscope is used to examine pipes in the field of industries, an operator who inserts the endoscope into a pipe has to incur a large load because of the complex bending of pipes.
On the other hand, Japanese Patents Nos. 2710384 and 2680111 have disclosed inserting direction detecting techniques. However, these techniques aim to detect a lumen seen within a field of view for imaging but do not have the advantage of detecting an inserting direction in case the lumen disappears from the field of view.
The present invention attempts to break through the foregoing situation. An object of the present invention is to provide an endoscope inserting direction detecting method for detecting an inserting direction in case a lumen disappears from a field of view for imaging.
Another object of the present invention is to provide an endoscope inserting direction detecting system capable of assisting in performing endoscopic examination smoothly by providing an operator with information of an inserting direction on the basis of the result of inserting direction detection.
Still another object of the present invention is to provide an endoscope inserting direction detecting method capable of prompting an operator to perform an appropriate manipulation in case an endoscope approaches too closely the mucosal surface of the lumen of the large intestine or in case there is difficulty in detecting an inserting direction.